From the past, there has been a thermoelectric conversion apparatus which converts heat into electricity using the Seebeck effect. In the thermoelectric conversion apparatus, a thermoelectric conversion material made of a semiconductor generating an electromotive force by giving a temperature gradient is used. As for the thermoelectric conversion material of the semiconductor, there are a p-type thermoelectric conversion material and an n-type thermoelectric conversion material depending on the difference of a conductive type. In the p-type thermoelectric conversion material and the n-type thermoelectric conversion material, when a temperature gradient direction is identical, an electromotive force direction is reversed.
FIG. 9 shows a general thermoelectric conversion apparatus in the prior art. The general thermoelectric conversion apparatus includes plural p-type thermoelectric conversion materials 501, plural n-type thermoelectric conversion materials 502 and plural electrodes 601 which are respectively electrically connected with two ends of p-type thermoelectric conversion material 501 and n-type thermoelectric conversion material 502 in each adjacent pair. Plural p-type thermoelectric conversion materials 501, plural n-type thermoelectric conversion materials 502 and plural electrodes 601 are covered and fixed by, for example, a ceramic substrate 604. Then, outer connection terminals 602 and 603 are connected with one end of the electrodes and the other end of the electrodes to output power.
In the prior art, it has been proposed to provide the thermoelectric conversion material in various shapes in the thermoelectric conversion apparatus.
For example, a configuration in which a p-type thermoelectric conversion material or an n-type thermoelectric conversion material is provided on an inner wall surface of a through hole of a porous heat-resistant insulator in a film shape is disclosed in PTL 1 (refer to FIG. 1 of PTL 1). In addition, a configuration in which the through hole where the p-type thermoelectric conversion material or the n-type thermoelectric conversion material is formed on the inner wall surface is formed in a circular truncated cone shape is disclosed in PTL 1 (refer to FIG. 3 of PTL 1).
In PTLs 2 and 3, a thermoelectric conversion module in which an n-type thermoelectric conversion material and a p-type thermoelectric conversion material are alternately inserted into a large number of through holes of a honeycomb structural body having flexibility is disclosed. In the thermoelectric conversion module, each end surface of the n-type thermoelectric conversion material and the p-type thermoelectric conversion material is connected through a metal piece.